function loader(source) {
    let code = `
        let style = document.createElement('style')
        style.innerHTML = ${JSON.stringify(source)}
        document.head.appendChild(style)
    `
    code = code.replace(/\\n/g,'\\\\n');
    console.log(code)
    return code
}
module.exports = loader

// 最后一个loader要返回一个可运行的字符串